Smelting zinc and the like



Dec. 27, 1932. w. A. OGG

SMELTING' ZINC AND THE LIKE Filed Jan. 15, 1931 4 Sheets-Sheet 1 Dec.27, 1932. w. A. OGG 1,892,114

SMELTING ZINC AND THE LIKE Filed Jan. 15, 1951 4 Sheets-Sheet 2 Wtru'mHEEL-Imp 010 g 819M307 72? 7 fli ys Dec. 27, 1932. w OGG 1,892,114

SMELTING ZINC AND THE LIKE Filed Jan. 15,1951 4 Sheets-Sheet s c cz, 0M?

Dec. 27, 1932. w. A. OGG 1,892,114

SMELTING ZINC AND THE LIKE Filed Jan. 15, 1931 4 Sheets-Sheet 4Invenior: Wm d; 0 19/43 M Z Patented Dec. 21, 1932 WILLIAM A. OGG, OFNEWTON, MASSACHUSETTS SME'LTING ZINC AND THE LIKE ApplicationfiledJanuary 15, 1981. Serial No. 508,326.

This invention relates to the smelting of zinc and like vdlatilizablemetals, and the object is to provide a novel method for sepa rating suchmetals from their compounds by 5 gaseous reduction under favorablethermal conditions with resultant advantages which will appear to thoseskilled in the art as the description proceeds.

The method may be well understood by the description of the operation ofthe one form of furnace suitable for practising the'same shown by way ofexample in the accompanying drawings, wherein:

*ig. 1 is a transverse section through the 1 furnace; f

Fig. 2 is a side elevation with parts broken away of one end of thesame;

Fig. 2a is asimilar view of the other end of the furnace; and Fig. 3 isa plan of the parts appearing in Fig. 2. v

eferring to Fig. 1, the furnace there shown takes the general form of atunnel having the side walls 5 and 7 and the roof 9 divided horizontallyinto a. flame chamber 11 and a reaction chamber 13 by a heat radiatingwall, herein shown asan arch 15 of suitable material having a highheat-conducting capacity, convenientl bricks of silicon carbide(carborundum). it one end, which may be termed the intake end (see Fig.2), an end wall 17 closes the flame chamber while the reaction chamberbeneath ma be closed by a suitable movable door 19. t the other end,

which may be termed the output end (see Fig. 2a), the flame chamber isclosed by the end wall 21 and the reaction chamber may be partiallyclosed by an end wall 23, there being, however, an ofltake opening 25which may be closed by a suitable door, not appearing as such in thefigure but the position of which is indicated by the showing of thehoisting mechanism 27. v

Gases may be burned in the combustion chamber 11 to heat the arch 15 sothat it will 7 radiate heat upon reaction material in the chamber 13below. I have herein shownmains 29 for fuel gas from which pipes 31discharge into the flame chamber through ports 33 while air forcombustion is supplied through mains 35through the passages 37 to ports39, the products of com ustion being disposed of in any suitable manner,not illustrated in the drawings.

Crude zinc oxide in the form of a fairly thick porous layer of finelydivided particles, conveniently roasted and sintered zinc ore, may besupported in the reaction chamber 13 on a foraminous grate 41 which maybe similar in construction to the well known grate utilized in theWetherill process for the manufacture of zinc oxide, this grate being ofa length corresponding to the length of the reaction chamber 13 andmovable in and out from the same through the doorway of door 19, beingherein shown as mounted on trucks 43 running on rails 45. Referring toFig. 2, the grate may be withdrawn to the left in the figure and onbeing returned toward the right the plow 47 may be suitably lowered bymeans of the adjusting mechanism 49 to scrape off any residues remainingupon the grate into bin 50, and the grate thus cleared passes beneathsuitable hoppers 51 t and 53 having the feeding devices 55 and 57respectively, herein illustrated as drivenby electric motors 59 and 61,from which hoppers material is deposited upon the grate, the chargebeing levelled off by the levelling bars 63 and 65, any surplus beingdischarged to so bins 64 and 66. I have herein shown two hoppers as itmaybe desirable to deposit first upon the grate from hopper 51 a layerof inert material, such as crushed gan e, to serve as a bed to receivethe crude oxi c, this bed further serving to facilitate the'distributionthrough the mass of oxide of the gas supplied through the grate aspresently to be described and as such being analogous to the similar beddescribed in the patent to ,Wemple 1,591,253, July 6, 1926. When thegrate thus loaded is pushed into the furnace, the door 19 is closed andthe reaction may f begin.

In accordance with my invention I utilize for smelting the zinc ahydrocarbon gas (paraflin gas) preferably in the form of socallednatural gas. For simplicit we may consider natural gas to consist omethane .as it does in large part. The higher hydrocarbon gases of thesame series will act similarly although the reaction will bespecifically difierent. The theoretical reaction is expressed by theequation Zn0+CH =Zn+ CO+2H Herein natural gas is supplied from main 67through pipes 69 and discharged to the reaction chamber beneath thegrate 41 and it penetrates through the openings of the grate and throughthe porous charge of crude zinc oxide. When the gas reaches the surfaceof this layer, it will encounter ore heated by radiation from the arch15 to a temperature favorable for reaction. As the reaction proceeds theupper surface of the layer wastes away, the products being gaseous orvaporous, and fresh surfaces are exposed to the radiant heat without theaccumulation of substantial amounts of residue since no solid reductionfuel is present and the only solid residuum is the gangue which may bepresent. There is thus practically no obstruction to the transmission ofheat by radiation from the arch 15 to the ore and a very high thermalefficiency is attained.

The zinc vapor and the gaseous products of the reaction pass lengthwiseof the furnace and are withdrawn through the port 25 (see Fig. 2a). Asthe arch 15 toward which the zinc vapors rise is heated, they aremaintained in a vaporous form until withdrawn from the chamber.

Externally of the furnace the metal vapors are separated from the gases,which latter are of a combustible nature and which will .recover aconsiderable portion of the heat units of the natural gas originallyused. As the volume of these gases is large, ll prefer to separate themetal values by chilling the efduent from the furnace suddenly, thus.causing the zinc to pass directly into solid form as blue powder forcollection for further treatment in any manner well known to the art. Ihave herein illustrated the gases as assing into a large, thin-walledchamber 71 in which they are suddenly cooled. Any blue powder separatingmay fall by gravity to bin 73. Chamber 71forms an intake to v a cyclone74, not completely shown but of a construction well known, in which thegases :are given-a whirling motion, and on account of the great weightof the blue powder the greater portion thereof is thrown out by thecentrifugal action and falls to collecting bin 75. From the cyclone theremaining gases pass through downtake 77 to chamber 79 which contains aconveyor 81 to collect and carry away any solid materials depositedtherein and finally pass to a bagging unit 83 where any remaining solidmaterial is separated from the gases which are led thence forutilization in any desired manner, whether for combustion in flamechamber 11 to provide heat for heating arch 15 or other I am aware thatthe invention may be em to the foregoing description to indicate thescope of the invention.

I claim:

1. The method of recovering metal values from crude oxides ofvaporizable metals characterized by spreading the crude oxide on'aforaminous support and exposing it beneath an externally heated wallwhile passing a reducing gas up through the support.

2. The method of recovering metal values from crude oxides ofvaporizable metals characterized by spreading the crude oxide in anextended layer and exposing the layer in opposition to an externallyheated wall to be heated by radiation therefrom, supplying a reducinggas to the heated oxide and withdrawing the evolved vapors from theclearance space between the oxide and wall.

3. The method of recovering metal values from crude oxides ofvaporizable metals characterized by spreading the crude oxide on a foraminous support and exposing it beneath an externally heated wall whilepassing hydrocarbon gas ,up through the support.

4. The method of recovering metal values from crude oxides ofvaporizable metals characterized by spreading the crude oxide in anextended layer, passing a reducing gas up through said layer whileexposing the up- WILLIAM A. OGG.

